1. Field of the Invention
The present invention relates to articles of footwear, and more particularly to articles of footwear adapted to support the traditional functions of footwear as well as to facilitate sliding over, for instance, a pipe, a rail, an edged surface or the like.
2. Description of the Prior Art
Athletic pursuits have long been a popular and pleasurable pastime, favored by young and old alike as an integral part of a healthy lifestyle. The number and variety of sports being played have increased steadily throughout the ages, and have seen an especially marked rise in the past two decades that has been fueled, at least in part, by substantial advances in equipment technology. For the great majority of athletic activities, the single most important piece of equipment is comprised of the footwear worn while engaging in the particular sport.
Athletic footwear is currently available in a bewildering array of styles, each specifically adapted for a particular use and ranging from lightweight, high traction running shoes to rigid, protective ski boots. More practical footwear is also available in many choices, from comfortable shoes for walking over extended periods of time to heavily insulated and reinforced work boots. Some articles of footwear are designed to facilitate a variety of activities such as running, walking, jumping, and skateboarding.
Skateboards consist of four wheels mounted on a semi-rigid board in a box configuration. The boards combine the excitement of skating with the mobility of running by enabling recreational access to a wide variety of surfaces and allowing the user to traverse sidewalks, roads, and other rollable surfaces. Highly athletic youthful users have discovered a relatively new use for skateboards. It has been discovered that the configuration of the skateboard also allows skaters to slide sideways across a protruding feature on a supporting surface, such as an edge, a ridge, a curb, a handrail, a pipe or the like, by engaging the underside of the board with, for instance, a pipe rail and then sliding laterally or longitudinally along the rail. Popularly referred to as "grinding," this is an exciting acrobatic maneuver that greatly increases the enjoyment of skateboarding by expanding the options available in using them.
As noted above, grinding maneuvers do not engage the wheels of the skateboard directly but rather the underside of the board, which is typically made of wood or hard plastic. These materials offer the requisite low coefficient of friction which enables the sliding maneuver across an abrasive surface such as a concrete curb. On the other hand, hard surface athletic footwear, such as running shoes, typically incorporate high friction cushioned soles that greatly aid in walking or running but inhibit sliding movements. More recently, other sports such as in-line skating and snowboarding have evolved to utilize grinding maneuvers. Unfortunately in order to perform grinding maneuvers with skateboards, in-line skates and snowboards, users must have a relatively high level of expertise. Furthermore, since skateboards, in-line sktaes, and snowboards are rather bulky, they are not convenient to carry around and are often unacceptable in everyday settings, such as office, bus, etc. Therefore, although enjoyable and exciting, grinding currently requires a high level of skill accompanied with specialized equipment adaptable in limited circumstances.
The idea of sliding across a surface while standing upright is not new, and various inventors have endeavored in the past to capitalize on this idea by proposing various devices to enable one to engage in this activity. One such device is built from a low friction material and attached to the sole of the shoe in the arch region, thereby allowing the user to slide across a smooth flat surface such as a dance floor. The device may extend below the heel of the shoe, and leaves the forefoot area exposed so that the user may engage the floor with the sole to be able to push off into a sliding maneuver. A device of this type is disclosed in U.S. Pat. No. 2,572,671 to Shaw. Another shoe that has been proposed incorporates a low friction region protruding centrally from the sole with high friction areas surrounding the protuberance. The user can thus engage the supporting surface by tilting the foot to lower the high friction areas of the sole, and can slide by pushing off and balancing on the protruding area. U.S. Pat. No. 1,984,989 to Reed discloses a device of this type. Both of the devices described above are designed for use on flat, smooth surfaces, such as dance floors, and neither device lends itself to use with a normal walking or running gait. Thus, although well adapted for their intended use as dance footwear, these devices are of limited usefulness and are not the ideal solution for persons desiring to engage in grinding activities.
Bicycle shoes have been proposed with steel soles to provide rigid support on the bicycle pedals. Work shoes and hiking boots have been proposed which incorporate metal shanks in the arch area to provide support against the bottom of the foot.
Shoes have also been proposed with exterior metal support but without concern for sliding over a rail or the like. Prior art footwear of this type is typically equipped with different types of reinforced arch supports, often in the form of plates attached to the bottom surface of the sole in the arch region for gripping a tool such as a shovel or a ladder rung. Devices of this type are disclosed in, among others, U.S. Pat. Nos. 881,079 to Jolitz and No. 5,134,791 to Gregory. Such devices are designed to support the user's foot while engaging in labor intensive activities such as digging or climbing a ladder, and are intended to restrict sliding on the support surface and to distribute shock. These plates are generally manufactured from a metal such as steel, and therefore provide an incidental and highly limited capacity for sliding on rough surfaces such as curb corners and the like.
One protective device proposed for strapping onto the bottom surface of the sole of a work boot is a rigid plate configured to be received on its top side against the bottom surface of the workman's shoe sole and extend forwardly under the ball of the foot. A transversely projecting rib is formed on the bottom of such plate to be positioned under the ball of the foot to retain the plate and, consequently, the shoe on the ladder rung. A device of this type is shown in U.S. Pat. No. 2,484,935 to DeRooy. Such devices, while satisfactory for their intended purpose, are not satisfactory for grinding activity. The devices are typically made oversized to be attached to different size and shaped shoes so the plate would typically not be formed on its opposite sides with any type of upwardly projecting rails to capture the shoe sole or form a close fit therewith for dependable riding thereon in a grinding manner. Additionally, without a break in the bottom surface of the shoe sole to form a recess therein to define a cavity for close fit relationship with the top surface of the plate, there would be some risk that the plate might shift relative to the shoe during the running or jumping activity thus creating risk of instability and consequent accidental falls and possible injury. Furthermore, such devices which place a transversely extending lateral flange under the ball or foot would be cumbersome to walk on and render the shoe apparatus ineffective as an athletic shoe.
Shoe heel bracing devices have also been proposed in the form of a generally L-shaped strut having opposed legs, one for attachment to the underside of the sole in the arch area of a high heel shoe and a second leg to be attached to the front surface of the high heel. Such devices are intended to be attached to the preexisting shoe sole surface and heel surface and the method of manufacture does not involve invading the bottom surface of the sole to form a cavity or involve a low heel athletic shoe which could reasonably be used in athletic maneuvers. A device of this type is shown in Australian Patent No. 216,903, issued Jan. 29, 1925.
What is now needed is an article of footwear that accommodates the traditional functions of walking, running and jumping, and that also facilitates sliding across surfaces such as concrete curbs and steel handrails by incorporating one or more suitable sliding surfaces. The sliding surfaces should not interfere with the other functions of the shoe, and therefore should not be comprised of unduly bulky or heavy elements and should not impede interaction of the sole with the supporting surface during a normal walking or running gait. The sliding surfaces will ideally be of low coefficient of friction and high abrasion resistance to withstand repeated sliding across abrasive supporting surfaces such as concrete.